US4939370A - Method of and device for inspecting and/or controlling metallization processes - Google Patents

Method of and device for inspecting and/or controlling metallization processes Download PDF

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Publication number
US4939370A
US4939370A US07/266,382 US26638288A US4939370A US 4939370 A US4939370 A US 4939370A US 26638288 A US26638288 A US 26638288A US 4939370 A US4939370 A US 4939370A
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United States
Prior art keywords
light beam
radiation
nominal value
scattered
reflected
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
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US07/266,382
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English (en)
Inventor
Heinrich Meyer
Waldfried J. L. Plieth
Martin Kurpjoweit
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Bayer Pharma AG
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Schering AG
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Assigned to SCHERING AKTIENGESELLSCHAFT reassignment SCHERING AKTIENGESELLSCHAFT ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: KURPJOWEIT, MARTIN, MEYER, HEINRICH, PLIETH, WALDFRIED J. L.
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
    • G01B11/0616—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material of coating
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601—Process or apparatus
    • C23C18/1619—Apparatus for electroless plating
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/1601—Process or apparatus
    • C23C18/1633—Process of electroless plating
    • C23C18/1675—Process conditions
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D21/00—Processes for servicing or operating cells for electrolytic coating
    • C25D21/12—Process control or regulation

Definitions

  • the present invention relates to a method of inspecting and/or controlling a process of metallization of a surface, and to a device for carrying out the method.
  • the method of the cyclic volt-ampere measurements in which primarily the redissolving of a minute amount of the deposition on an inner electrode is tested, represents a more direct approach to the processes on the electrodes.
  • this method delivers directly interpretable data which could be used for controlling the metallization process only in very limited scope and, in addition, is susceptible to interferences caused by even the smallest contaminants.
  • one feature of the method of this invention resides in the steps of exposing a surface portion being metallized to a reference radiation, measuring the amount of radiation which is scattered or reflected from said surface portion to determine a deviation from a nominal value, and varying parameters of the metallization process to neutralize the measured deviation.
  • the device for inspecting and/or controlling a process of metallization of a surface comprises a source of radiation for generating a beam of a monochromatic, substantially coherent electromagnetic radiation, preferably in the visible or ultraviolet energy range, a first optical means for focusing the radiation beam on a surface portion being metallized, a second optical means for collecting the part of radiation beam that is directly reflected or diffused or scattered from the irradiated metal layer on the surface portion, and a radiation detector for measuring intensity of radiation collected by the second optical means.
  • the method of this invention is based on an observation that hitherto has not been known, namely that the intensity of light scattered from or also directly reflected from the deposited metal layer depends on optical properties of the metal layer and is affected in a very characteristic manner by the microstructure or microtexture of the deposited surface layer.
  • the microstructure or microtexture is conditioned almost by all technological properties of the deposited metal, for example by its ductility, hardness, corrosion resistance and optical appearance among others.
  • the method of this invention is carried out by means of a scattered light measuring apparatus which operates according to the principle of the light scattering on a surface portion being metallized; by means of the scattered light measurement the quality both of galvanically and of chemically deposited metal layers can be monitored in situ.
  • the measurement of the scattered light can be coupled with a complete electrochemical testing arrangement.
  • the latter combination makes it possible to measure the scattered light under exactly defined electrochemical conditions. These conditions are predetermined by the potential and current density; at the same time they can be also characterized by electrochemical measurements, also by those which are time dependent, as well as by measurements of the complex impedance for alternating current and of the current/time behavior after a change of the potential.
  • the testing can be performed either by means of taking discrete samples or measurements or continuously by using a throughflow apparatus.
  • the measured scattered light shows the optical quality or condition of the measured surface and in addition provides a picture of the crystallinity and of the microtexture of the deposited metal layer. In this manner it is achievable to determine in situ for example the quality of a metallization bath and by controlling its parameters, to control the deposited metal layer.
  • the method of this invention enables the control of instant metal deposition under the presentation of all electrochemical metallization parameters, which feature has not been possible in prior art processes of this kind.
  • the invention makes it possible to supervise or control the metal deposition by means of different prior art methods whose parameters are regulated in response to the evaluation of the measured values of the reflected or scattered radiation intensity whereby the total intensity refers to within a narrow circle cutout from the impinging light beam.
  • Characteristic points or regions of the time dependency of the directly reflected intensity for example maxima, minima, half width of maxima and minima, turning points, steepness of curves, integrated intensity-/time functions;
  • the time variations of the reflection spectrum particularly the time variation of the structures in the reflection spectrum such as maxima, minima, and half width.
  • the measured data can be stored and evaluated in a microprocessor and then directly fed into the metallization bath to influence the process.
  • Parameters which can be controlled in this manner are the current density during the metal deposition, the electrode potential, the temperature, the composition of the bath and the convection in the bath among others.
  • the method of this invention can be applied with a particular advantage for all current metallization processes, particularly for:
  • the currentless metallization that means the chemical autocatalytic reduction of metal ions on activated upper surfaces
  • FIG. 1 shows schematically a circuit diagram of the device for checking and/or controlling a process of metallization of a surface
  • FIG. 2 shows a time plot of scattered light intensity for a metallization bath including three different amounts of an inhibitor solution
  • FIG. 3 is a plot diagram of scattered light intensity versus the thickness of a metallization layer for different types of metallization baths.
  • FIG. 4 is a time plot of the current density for two production baths of FIG. 3.
  • RDE indicates a rotary disc electrode
  • RDE SG indicates a control apparatus and power supply 1' for the RDE
  • MLC indicates a mechanical light beam chopper 2
  • OLD indicates an optical light detector 3 with a power supply NG 3'
  • POT a potentiometric device or a potentio-stat 4 with an interface
  • GE, ME and BE indicative of a counterelectrode 5, a measuring electrode 6 and a reference electrode 10
  • PL indicates a plotter
  • LIA indicates a 2-phase lock-in amplifier 8
  • MC indicates a microcomputer 9 having a IEEE 488 interface 9'
  • DMM indicates a digital multimeter 11
  • PR is a printer 12
  • XY-Schr indicates a plotter 13.
  • the device of this invention includes a light source 14, preferably in the form He/Ne-laser or a tunable color substance laser having a broad frequency range.
  • the light emanating from the light source 14 is transmitted perpendicularly or deviated at an angle to impinge preferably in the form of focused light beam 15 on a surface 16 being metallized in a bath 19.
  • the angle of incidence of the transmitted light beam can be varied by means of suitable optical means, such as lenses or reflecting mirror 18! If desired the transmitted light beam 15 can be chopped up by a mechanical chopper 2.
  • the amount of light 17' scattered or reflected from the surface 16 is measured either under a characteristic angle to the surface 16 whereby the angle can be varied within broad range or as illustrated in FIG.
  • the light 17' which has been scattered or reflected over a wide variety of angles, is focused and integrated into a measuring light beam 17.
  • the focusing and collecting or integration of the light 17' can be carried out by means of lenses and/or mirror 18.
  • the intensity of the light reflected by the mirror 18 is measured by light intensity measuring detector 3.
  • the light intensity measuring detector is coupled to an integrated electrochemical measuring arrangement including a component potentiometric device or potentio-stat 4, a function generator for generating the controlling potentials, a lock-in amplifier 8 for measuring extremely low intensities of the scattered reflected light and simultaneously measuring the complex impedances of the alternating current, a transient recorder for measuring the time pulse of the scattered reflected light and simultaneously the time course of the current and of capacity.
  • modified electrochemical standard cells provided with a measuring electrode 6, a reference electrode 10 and a counterelectrode 5 can be employed.
  • the measuring apparatus can be also made in the form of a through-flow cell for an automatic on line monitoring of the bath 19, as indicated in FIG. 1.
  • the automatic inspection or control is performed by electronic devices controlled by the microprocessor 9 whose input and output interface 9' serves for receiving the detected data and outputting the processed data for controlling the corresponding changes of the process parameters.
  • FIG. 2 illustrates the time variation of the intensity of the measured scattered light in a metallization process using current density of 25 mA/cm 2 in a basic electrolyte+35.0 mg/1 chloride+4 ml of wetting agent solution and an additive of the following amounts of an inhibitor solution per each liter of electrolyte: (A) 0.0 ml; (B) 0.2 ml; (C) 1.0 ml; and (D) 2.0 ml of the inhibitor solution per liter.
  • FIG. 3 illustrates a plot diagram of the changes of the measured scattered light intensity at 25 mA/cm 2 of the current density versus the thickness of the deposited layer for: (A) a production bath; (B) another production bath; (C) new charge of a galvanic copper bath.
  • FIG. 4 shows a time plot of the current density at 150 mV versus NHE for the production bath (A) and the production bath B of FIG. 3.
  • the method can be used for supervising an acid copper bath a typical composition of which consists of:
  • the metal deposition is periodically taken up on an inert electrode made for example of platinum, gold, retort carbon, and the like. After a certain time period (typically 10 to 100 seconds) the deposited amount of metal is reoxidated. For long term tests a copper electrode can be employed.
  • the electrolytic bath is operated at a typical current density of 5 A/dm 2 . From a large number of measurements, a typical time course of the measured scattered light intensity, integrated over a circular segment, is illustrated in FIG. 2.
  • the curves B and C in FIG. 2 correspond to a good bath.
  • Curves A and D indicate unusable deposits or precipitation.
  • the conclusions from the scattered light measurements can be further supported by evaluating other measurements. For this prupose, ground or polished sections, the optical appearance and hardness of the deposited material are suitable which in all cases can be correlated with typical differences of the reflection/time course. Differences can be also recorded in the electrochemical measurements which complement the reflection measurements.
  • FIG. 3 illustrates a current density/time function after a potential search in the range of the metal deposition on platinum.
  • FIG. 4 illustrated the corresponding scattered light-time function of two typical production baths: A still intact, B greatly exhausted; C in FIG. 4 shows the curve of scattered light of a new introduced bath. From the ascent of the scattered light/time function to the first maximum (positive or negative) the bath can be evaluated. The corresponding course of the current support this finding, nevertheless they are less characteristic.
  • nickel 60-100 g/l of nickel as nickel sulfate NiSO 4 and nickel chloride NiCl 2 ;
  • condition of electrodes is predetermined by the mixing potential of the Redox components of the electrolyte.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • Automation & Control Theory (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
  • Chemically Coating (AREA)
  • Chemical Vapour Deposition (AREA)
US07/266,382 1987-11-02 1988-11-02 Method of and device for inspecting and/or controlling metallization processes Expired - Fee Related US4939370A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19873737489 DE3737489A1 (de) 1987-11-02 1987-11-02 Verfahren zur kontrolle und/oder steuerung von metallisierungsprozessen und vorrichtung hierfuer
DE3737489 1987-11-02

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EP (1) EP0316598A1 (de)
JP (1) JPH01208500A (de)
AT (1) AT395322B (de)
DE (1) DE3737489A1 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5384153A (en) * 1993-03-10 1995-01-24 At&T Corp. Monitoring electroless plating baths
US6350361B1 (en) * 1999-02-17 2002-02-26 Scitex Digital Printing, Inc. Real time control device for electroformation, plating and deplating processes
US6684172B1 (en) * 2001-12-27 2004-01-27 Advanced Micro Devices, Inc. Sensor to predict void free films using various grating structures and characterize fill performance
US6824813B1 (en) * 2000-04-06 2004-11-30 Applied Materials Inc Substrate monitoring method and apparatus
WO2005028705A1 (en) * 2003-09-19 2005-03-31 Applied Materials, Inc. Apparatus and method of detecting the electroless deposition endpoint
US20060062897A1 (en) * 2004-09-17 2006-03-23 Applied Materials, Inc Patterned wafer thickness detection system
US20090120676A1 (en) * 2007-10-29 2009-05-14 Leonhard Kurz Stiftung & Co. Kg. Process for the production of a conductor track structure

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10058566C2 (de) * 2000-08-03 2002-10-31 Va Q Tec Ag Folienumhüllter, evakuierter Wärmedämmkörper und Herstellungsverfahren für diesen
DE102006009460A1 (de) * 2006-03-01 2007-09-06 Infineon Technologies Ag Prozessgerät und Verfahren zur Bestimmung der Temperatur eines Substrats in dem Prozessgerät
DE202007009859U1 (de) 2007-07-14 2007-10-25 Dechema Gesellschaft Für Chemische Technik Und Biotechnologie E.V. Vorrichtung zur spektroskopischen Charakterisierung von an einer Elektrode gebildeten elektrochemischen Reaktionsprodukten

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4073964A (en) * 1974-03-05 1978-02-14 Kollmorgen Technologies Corporation Process for controlling metal thickness, and deposition and degradation rates
SU896401A1 (ru) * 1979-07-30 1982-01-07 Предприятие П/Я М-5539 Способ контрол шероховатости поверхности
US4311725A (en) * 1978-08-18 1982-01-19 National Research Development Corporation Control of deposition of thin films
US4583861A (en) * 1981-08-12 1986-04-22 Tokyo Shibaura Denki Kabushiki Kaisha Surface condition judging apparatus
US4624857A (en) * 1984-02-03 1986-11-25 Schering Aktiengesellschaft Method for automatic control of galvanic deposition of copper coatings in galvanic acid copper baths
US4653908A (en) * 1983-12-02 1987-03-31 Hitachi, Ltd. Grazing incidence reflection spectrometer
US4692346A (en) * 1986-04-21 1987-09-08 International Business Machines Corporation Method and apparatus for controlling the surface chemistry on objects plated in an electroless plating bath
US4831324A (en) * 1986-03-20 1989-05-16 Hitachi, Ltd. Method and apparatus for analyzing the electrode inpedance

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Publication number Priority date Publication date Assignee Title
US2895888A (en) * 1957-10-07 1959-07-21 Industrial Nucleonics Corp Electrolytic plating apparatus and process
US3827963A (en) * 1973-01-02 1974-08-06 Electrometallurgical Sales Reflectivity-responsive control system for electrolytic finishing apparatus
GB2181835B (en) * 1985-10-01 1990-03-21 Univ Liverpool Monitoring device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4073964A (en) * 1974-03-05 1978-02-14 Kollmorgen Technologies Corporation Process for controlling metal thickness, and deposition and degradation rates
US4311725A (en) * 1978-08-18 1982-01-19 National Research Development Corporation Control of deposition of thin films
SU896401A1 (ru) * 1979-07-30 1982-01-07 Предприятие П/Я М-5539 Способ контрол шероховатости поверхности
US4583861A (en) * 1981-08-12 1986-04-22 Tokyo Shibaura Denki Kabushiki Kaisha Surface condition judging apparatus
US4653908A (en) * 1983-12-02 1987-03-31 Hitachi, Ltd. Grazing incidence reflection spectrometer
US4624857A (en) * 1984-02-03 1986-11-25 Schering Aktiengesellschaft Method for automatic control of galvanic deposition of copper coatings in galvanic acid copper baths
US4831324A (en) * 1986-03-20 1989-05-16 Hitachi, Ltd. Method and apparatus for analyzing the electrode inpedance
US4692346A (en) * 1986-04-21 1987-09-08 International Business Machines Corporation Method and apparatus for controlling the surface chemistry on objects plated in an electroless plating bath

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5384153A (en) * 1993-03-10 1995-01-24 At&T Corp. Monitoring electroless plating baths
US6350361B1 (en) * 1999-02-17 2002-02-26 Scitex Digital Printing, Inc. Real time control device for electroformation, plating and deplating processes
US6824813B1 (en) * 2000-04-06 2004-11-30 Applied Materials Inc Substrate monitoring method and apparatus
US6684172B1 (en) * 2001-12-27 2004-01-27 Advanced Micro Devices, Inc. Sensor to predict void free films using various grating structures and characterize fill performance
WO2005028705A1 (en) * 2003-09-19 2005-03-31 Applied Materials, Inc. Apparatus and method of detecting the electroless deposition endpoint
US20050088647A1 (en) * 2003-09-19 2005-04-28 Applied Materials, Inc. Apparatus and method of detecting the electroless deposition endpoint
US7534298B2 (en) 2003-09-19 2009-05-19 Applied Materials, Inc. Apparatus and method of detecting the electroless deposition endpoint
CN100564592C (zh) * 2003-09-19 2009-12-02 应用材料公司 对无电沉积的终点进行检测的装置和方法
US20060062897A1 (en) * 2004-09-17 2006-03-23 Applied Materials, Inc Patterned wafer thickness detection system
US20090120676A1 (en) * 2007-10-29 2009-05-14 Leonhard Kurz Stiftung & Co. Kg. Process for the production of a conductor track structure

Also Published As

Publication number Publication date
AT395322B (de) 1992-11-25
DE3737489A1 (de) 1989-05-18
ATA266588A (de) 1992-04-15
JPH01208500A (ja) 1989-08-22
EP0316598A1 (de) 1989-05-24

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